This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The proposed experiments involve the characterization of small protein crystals. The protein in question is a fairly large (~500 kDa) complex of two different proteins. The crystals stain blue in the presence of crystal violet dye, indicating that they are composed of protein. However, the crystals grow only as small plates, with dimensions of approximately 100-200 microns on the plate face and 50 microns measured orthogonal to the face. The crystals are to be studied to determine extent of diffraction, twinning and mosaicity. Potential improvements in cryo-conditions will also be examined. The crystals have been grown in a variety of different substrates. The effect of these substrates upon the diffraction properties will be studied as well. Determination of space group and the collection of a native set for these crystals would be the ultimate goal.